Fluid pressure operated motor



Jan. 23, 1962 w. STELZER 3,017,866

FLUID PRESSURE OPERATED MOTOR Filed Aug. 3, 1959 3 Sheets-Sheet 1ATTORNEY Jan. 23, 1962 Filed Aug. 3, 1959 W. STELZER FLUID PRESSUREOPERATED MOTOR 3 Sheets-Sheet 2 I3 \9 g 24 H 22 \oo a7 3% {O 61 82 \o ae5 $0 53 5n 3 5340 4a, 5 9o mm 58 41 444 L? as 77 \5 G I INVENTORWILL/AM 6 TELZEE ATTORNEY Jan. 23, 1962 Filed Aug. 5, 1959 W. STELZERFLUID PRESSURE OPERATED MOTOR 3 Sheets-Sheet 3 INVENTOR 4 WILL/AM5TELZEE ATTORNEY United States tent @tice 3,017,866 FLUID PRESSUREOPERATED MGTOR William Stelzer, Bloomfield Hills, Mich, assignor toKelsey-Hayes Company, Detroit, Mich, a corporation of Delaware FiledAug. 3, 1959, Ser. No. 831,246 10 Claims. ((31. 121-41 This inventionrelates to a fluid pressure operated motor and more particularly to sucha motor especially adapted for use in operating motor vehicle brakes.

There are two general types of vehicle booster brake motors of theelastic fluid pressure type in common use. One such motor is of the airsuspended type in which motor chambers on opposite sides of the motorpiston are normally at atmospheric pressure and the motor is operated byexhausting air from one of said chambers to create differentialpressures on opposite sides of the motor piston. The other type of motoris of the vacuum suspended type in which the motor chambers on oppositesides of the piston thereof are normally evacuated and motor operationis effected by admitting air to one of the motor chambers. Generallyspeaking, the air suspended type of motor has certain advantages, suchas simplicity, over the vacuum suspended type, but is somewhatdisadvantageous as compared with the vacuum suspended type since thelatter responds much more rapidly to operation of the control valvemechanism which admits air to one of the motor chambers.

An important object of the present invention is to provide a motor ofthe air suspended type which possesses the advantage of a vacuumsuspended motor in that it provides for the more rapid evacuation of oneof the motor chambers upon operation of the control valve mechanism.

More specifically, an object of the invention is to provide an airsuspended motor having embodied as a part thereof a vacuum reservoir ofsubstantial capacity, connected to a source of vacuum, such as theintake manifold of the vehicle engine, to be normally evacuated andconnectible to the variable pressure chamber of the mtor upon operationof the valve mechanism to eflFect an extremely rapid evacuation of suchchamber of the motor.

A further object is to provide a motor of this type wherein the pressureresponsive unit of the motor, which divides the casing thereof toprovide a constant pressure chamber and a control or variable pressurechamber, is provided with a vacuum reservoir of substantial capacitywhereby, when the follow-up control valve mechanism of the motor isoperated, the control or variable pressure chamber of the motor isconnected to the vacuum reservoir referred to, to effect a rapidevacuation of the motor control chamber, such evacuation being much morerapid than is true of aconven'tional air suspended motor in which avacuum line is connected to the motor control chamber upon operation ofthe valve mechanism.

Other objects and advantages of the invention will become apparentduring the course of the following description.

In the drawings I have shown one embodiment of the invention. In thisshowing:

FIGURE 1 is a diagrammatic view showing the braking system of a motorvehicle as a whole including the motor of the present invention;

FIGURE 2 is an enlarged fragmentary axial sectional view through themotor and associated elements, the parts being shown in normal otfpositions;

FIGURE 3 is a fragmentary sectional view of a portion of a motor showingthe parts in operative positions; and

lifil'hdiiii Patented Jan. 23, 1%62 FEGURE 4 is a section on line 4-4 ofFIGURE 2.

Referring to FIGURE 2, the numeral 10 designates the motor as a wholecomprising casing sections 11 and i2 suitably connected together as at13 by any desired type of casing connection, forming no part of thepresent invention. The motor is provided therein with a pressureresponsive unit indicated as a whole by the numeral l4. Such unitcomprises an annular shell 15 shaped in cross section as shown in FIGURE2 and providing therein a vacuum reservoir 16 of substantial capacity.The body or shell 15 is connected to the inner bead 17 of a rollingdiaphragm 18 the outer periphery of which is provided with a bead 19clamped between the casing sections ill and 12. An elbow 22 is connectedto and communicates with the shell 15 and has its outer end connected bya flexible hose 23 with a source of vacuum such as the intake manifoldof the vehicle engine. It will become apparent that the elbow 22 moveswith the pressure responsive unit and the casing 12 is provided with aslot 24 to accommodate movement of the elbow 22.

The pressure responsive unit further comprises preferably die-cast bodymembers 28 and 29 secured together as at 30. These body sections providean internal annular chamber 311 in fixed communication with thereservoir 16 through a passage 32.

The body member 29 is provided with an annular valve seat 33 normallyengaged by a resilient annular valve 34. This valve is carried by a body35 sealed with respect to the body 28 by an annular diaphragm 36. Thevalve 34 is biased to the right to its normal position in FEGURE 2 by aspring 37. A space radially within the valve seat 33 forms a chamber 40for a purpose to be described.

An axially movable pedal operable member 42 is slidable in the body 29,such body being provided with an annular flange 43 forming a bearing forthe member 42. An annular flange 44 on the member 42 engages the bearing43 to limit movement of the member 42 to its off position shown inFIGURE 2.

The member 42 is provided with an annular valve seat to radiallyinwardly of and concentric with the valve seat 33. The space Within thevalve seat 46 communicates through a port 47 with a space 43 within themember 42, such space being open to the atmosphere, as described below.i

Movement of the body 42 to the left of its oil position in FIGURE 2 iseffected .by means of a rod 50 projecting axially through the space 48and connected in any suitable manner with the member 42. Such connectionin the present case includes a spherical head 51 and an adjacentresilient collar 4-2, both arranged in a pilot extension 53 formedintegral with the member 42 and slidable in a bore 54 formed in an axialextension 5'5, preferably integral with the body member 28. A spring 56biases the pilot extension 53 and member 42 rearwardly or to the rightin FIGURE 2.

A plate 60 is rigidly fixed to the member 42 and is provided withcircumferentially spaced openings 61 through which project pins 62(FIGURES 2 and 4') fixed to the body 29, for a purpose to be described.Against the plate 60 is arranged an annular diaphragm 64 having itsinner periphery secured with respect to the bodies 28 and 29 as shown inFIGURE '2. The outer periphery of the diaphragm 64 is provided with arelatively heavy head 65, one side of which is formed as an annularflange 66 normally spaced from, but movable into engagement with, theadjacent wall 67 of the shell 15. The flange 66 is grooved as at 68 (seethe lower portion of FIGURE 2) to maintain, under :all conditions,communication between the space 69 to the left i f the diaphragm 64 andthe constant pressure chamber 70 of the motor in which atmosphericpressure is always present. At the side of the pressure responsive unit14 opposite the chamber 70, the motor is provided with a control orvariable pressure chamber 71 which communicates with the chamber 70,under conditions to be described, when the motor is inoperative, thechamber 71 ;being connectible to the vacuum reservoir 16 to eiiectoperation of the motor.

A second annular plate 75 at its inner periphery normally seats againsta snap ring 76 carried by the member 42. The plate 75 has its outerperiphery seating in an annular groove 77 in the diaphragm bead 65. Acover plate 80 has its inner periphery bonded to a sealing diaphragm 81surrounding and snugly fitting the rod 50, the plates 75 and 80 formingtherebetween an air chamber 82. The plate 80 has its outer peripheryfixed relative to the plate 75 by threaded studs 84, the heads 85 ofwhich are preferably welded to the plate 75. These stud heads,therefore, serve to space the outer periphery of the plate 80 from theplate 75, thus providing an air passage or passages 86 communicatingwith the constant pressure motor chamber 70, which in turn is alwaysopen to the atmosphere through the slot 24. An annular air cleaner 87 isarranged between the plates 75 and 80, thus supplying clean air to thespace 48. The plate 80 is biased to the right in FIGURE 2 by a spring90, and since the plate 80 is fixed to the plate 75, this spring biasesthe radially inner periphery of the plate 75 into engagement with thesnap ring 76.

The plate 75 is shouldered as at 94, and between such shoulder and themember 42 is arranged an annular diaphragm 95. Such diaphragm forms withthe plate 75 a chamber 96 open to the chamber 82 as at 97. An annularpressure plate 98 is fixed to the diaphragm 95 and constantly engagesthe adjacent ends of the pins 62 for a purpose to be described.

A chamber 100 is formed between the plates 60 and 75 and is in fixedcommunication with the motor control chamber 71 through openings 61 andthrough a passage 101 formed through the body members 28 and 29. Thechamber 100 also is in fixed communication with the valve chamber 40through a passage 102.

Since the valve chamber 40 normally is in communi cation with,theatmosphere through passage 47, space 48 and air chamber 82, and sincethe valve chamber 40 normally communicates with the motor chamber 71through passages 102 and 101, it will be noted that atmospheric pressureis normally present in the motor chambers 70 and 71. The pressureresponsive unit is biased to the OE position shown by a return spring105, and the motor casing 12 may be provided with circumferentiallyspaced rubber bumpers 106 against which the outer periphery of the shell15 is normally seated.

The left-hand end of the axial extension 55 (FIGURE 2) terminates in amaster cylinder plunger 110 operable in a master cylinder 111 providedwith the usual reservoir 112. Operation of the motor displaces fluidfrom a master cylinder chamber 113 through lines 114 to the vehicleWheel cylinders 115 (FIGURE 1). Operation of the valve mechanism of themotor is effected through depression of a brake pedal 116 pivoted as at117 to the push rod 50. This rod is preferably connected to the motorcasing 12 by a conventional flexible boot 118.

Operation The motor chambers 70 and 71 are normally at atmosphericpressure, as stated above. Operation of the motor is effected bydepressing the brake pedal 116 to operate the rod 50 and thus transmitmovement to the member 42 to move it to the left in FIGURE 2. Initialmovement of the member 42 engages the valve seat 46 with the valve 34,thus disconnecting the valve chamber 40 from the atmospheric passage 47.The valve parts will now be in lap position. Slight additional movementof the member 42 will cause the valve seat 46 to move the valve 34 tothe left away from the seat 33, thus cracking the valve chamber 40 tothe chamber 31. This chamber is in fixed communication with the vacuumreservoir 16 through the passage 32, and accordingly air will beexhausted from the motor chamber 71 through passages 101 and 102. Itwill be noted in this connection that the diaphragm 64, plate anddiaphragm seal the passages 101 and 102 from the motor chamber 70, andaccordingly pressure in the chamber 71 will be controlled, as described,by operation of the valve mechanism.

The exhaustion of air from the chamber 71 establishes differentialpressures on opposite sides of the pressure responsive unit 14, and suchunit accordingly moves to the left in FIGURE 2 to operate the plunger110, thus displacing fluid from the chamber 113 into the brake lines 114and thus to the wheel cylinders 115 to apply the brakes. Obviously, thevalve mechanism provides a follow-up action of the pressure responsiveunit 14 and the plunger 110 with respect to the pedal operable rod 50.If pressure is to be applied to the plunger 110 beyond the point atwhich maximum energization of the motor takes place, forces applied tothe pilot extension 53 will transmit forces direct to the axialextension 55, as will be obvious.

When the brakes are to be released, the operator will release the pedal116, whereupon the spring 56 will move the valve seat 46 to the right.The spring 37 will cause the valve 34 to follow such movement until thevalve engages the seat 33,-whereupon the valve seat 46 will move awayfrom the valve 34 to connect the motor chamber 71 to the atmosphere. Thereturn spring 105 will move the pressure responsive unit to its oilposition, such movement being limited and silenced by the rubber bumpers106.

The means comprising the diaphragm 64, plate 75, etc. provides forreaction against the brake pedal. Such means will be generallydescribed, but forms no part of the present invention, being disclosedand claimed in my copending application Serial No. 832,287, filed August7, 1959, now Patent No. 2,976,850. As previously stated, the pressureplate 98 is always in engagement with the pins 62. Upon initialoperation of the valve mechanism to energize the motor, air will beexhausted from the chamber 100, which communicates with the passage 102through openings 61. Atmospheric pressure in the chamber 96 actingagainst the diaphragm 95 applies pressure to the body 29 through thepins 62. The purpose of the diaphragm 95 is to subtract from theeffective pressure areas of the plate 75 for a purpose to be described.

Atmospheric pressure acts on the remote faces of the diaphragm 64 andplate 75 while sub-atmospheric pressure will exist in the chamber uponoperation of the valve mechanism. The effective pressure areas of thediaphram 64 and the plate 75 may be such as to balance each other so asto transmit no reaction force tending to oppose movement of the rod 50.It will be noted that atmospheric pressure acting on the remote faces ofthe diaphragm 64 and plate 75 tend to move these elements toward eachother, but such movement is opposed by the counter-reaction spring 90.Thus the plates 60 and 75 move as a unit during initial operation of themechanism. When differential pressures alfecting the pressure responsiveunit increase incident to engagement of the brake shoes with the brakedrums, pressure acting against the right-hand face of the plate 75 (FIG-URES 2 and 3) will move this plate against the loading of the spring 90,whereupon the flange 66 engages the wall 67 of the shell 15, as shown inFIGURE 3. From this point on, there will be no balancing pressuresaffecting the diaphragm 64 and its plate 60 and the plate 75,

'and there will be a net pressure acting to the right against thediaphragm 64 and plate 60, which will be transmitted to the rod 50 toprovide reaction against the brake pedal. In some installations, it isdesirable to provide initial brake reaction. Under such conditions, thediaphragm 95 will be made of larger area to reduce the effective area ofthe plate 75 open to atmospheric pressure in the chamber 70. With suchan arrangement, there will be an initial net pressure acting to theright against the diaphragm 64 and plate 60 to provide some reactionagainst the brake pedal, which reaction will be increased when theflange 66 engages the wall 67.

As previously stated, the. reaction means just generally described formsper so no part of the present invention, but is disclosed and claimed inthe copending application identified above. The important feature of thepresent invention lies in the provision of a motor which has theadvantages of an air-suspended motor, but which provides the advantageof a vacuum-suspended motor in that it effects an extremely rapidevacuation of the motor chamber 71 when the valve mechanism is operated.In other words, if the vacuum line from the intake manifold wereconnected directly to the chamber 31, an appreciable time element wouldbe required for the evacuation of the motor chamber 71. Thisdisadvantage is overcome by providing the vacuum reservoir 16 as a partof the motor, and more specifically as a part of the pressure responsiveunit. This reservoir is of substantial capacity, and it will be apparentthat when the valve seat 46 is closed and the valve seat 33 opened, airwill be almost instantaneously evacuated from the chamber 71.Accordingly there will be provided an extremely rapid response of themotor to operation of the valve mechanism, substantially the same astakes place in the operation of the valve mechanism of avacuum-suspended motor. Moreover, with a conventional check valvearranged in the vacuum line to the intake manifold, the reservoir 16serves to provide what may be termed reserve vacuum so that if thevehicle engine stalls, the reserve capacity of the reservoir 16 willprovide for the operation of the brakes without the necessity for usinga conventional reserve vacuum tank in conjunction with the system. Thecost of such reserve vacuum tank is substantial, Whereas the formationof the shell adds little or nothing to the expense involved in themanufacture of the present motor. Obviously, the construction eliminatesthe disadvantage of a dead space of substantial volume which has to beevacuated each time the brake is operated, thus requiring less vacuum tooperate the motor. At the same time, atmospheric pressure in the motorchamber 71 when the mechanism is inoperative eliminates sealing troublessometimes occurring in vacuum suspended motors, through which leakage ofbrake fluid occurs around the master cylinder plunger. Moreover, whilethe reservoir 16 provides for substantially instantaneous evacuation ofthe chamber 71 to provide a rapid response of the motor to operation ofthe brake pedal, re-evacuation of the reservoir 16 occurs very rapidlythrough exhaustion of air through the pipe 23 to restore normalreservoir conditions. As a matter of fact, this occurs during brakeoperation, and accordingly the reserve of vacuum is always ready foruse.

It is to be understood that the form of the invention shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the shape, size, and arrangement of the parts may bemade as do not depart from the spirit of the invention or the scope ofthe appended claims.

I claim:

1. A fluid pressure motor mechanism comprising a casing, a pressureresponsive unit therein dividing said casing to form a constant pressurechamber and a control chamber, said pressure responsive unit having afluid reservoir therein connectible to a source of pressure differ entfrom the atmosphere, and a control valve mechanism comprising a body andhaving connection with said chambers and with said reservoir andnormally connecting said chambers to each other to balance pressures onopposite sides of said pressure responsive unit, said reservoir being ofrelatively small internal diameter and having its inner periphery fixedto said valve body, said reservoir being of relatively large externaldiameter and of substantial length axially of the motor mechanism, saidvalve mechanism being operable to disconnect said chambers from eachother and connect said control chamber to said reservoir to effect arapid motor-energizing change of pressure in said control chamber.

2. A mechanism according to claim 1 wherein said constant pressurechamber communicates with the atmosphere, said reservoir being a vacuumreservoir connectible to a source of vacuum whereby operation of saidvalve mechanism effects a rapid evacuation of said control chamber.

3. A fluid pressure motor mechanism comprising a casing, a pressureresponsive unit therein dividing said casing to form a constant pressurechamber and a control chamber, said pressure responsive unit comprisinga,

radially relatively small axial member and a radially outer shell fixedat its inner periphery to said axial member and forming a fluidreservoir connectible to a source of pressure different from theatmosphere, said reservoir being of relatvely large external diameterand of substantial length axially of the motor mechanism, a controlvalve mechanism carried by said axial member and having a valve chamberin fixed communication with said control chamber and normallycommunicating with said constant pressure chamber, said valve mechanismhaving a second chamber communicating with said reservoir and normallydisconnected from said valve chamber, said valve mechanism comprising amanually operable element movable from normal position to disconnectsaid valve chamber from said constant pressure chamber and connect it tosaid second chamber to efiect a rapid motor-energizing change inpressure in said control chamber.

4. A mechanism according to claim 3 wherein said constant pressurechamber is open to' the atmosphere, said reservoir being a vacuumreservoir connectible to a source of vacuum whereby the opening of saidvalve chamber to said second chamber eifects a rapid evacuation of saidcontrol chamber.

5. A mechanism according to claim 3 provided with means connected tosaid manually operable member and exposed to pressures in said constantpressure and control chambers to oppose movement of said manuallyoperable member away from normal position after said valve chamber hasbeen connected to said second chamber.

6. A mechanism according to claim 3 wherein said constant pressurechamber is open to the atmosphere, said reservoir being a vacuumreservoir connectible to a source of vacuum whereby the opening of saidvalve chamber to said second chamber effects a rapid evacuation of saidcontrol chamber, and fluid pressure responsive means exposed topressures in said control and constant pressure chambers to opposemovement of said manually operable member away from normal positionafter said valve chamber has been connected to said second chamber.

7. A fluid pressure rnotor comprising a casing and a pressure responsiveunit forming therewith a control chamber, said pressure responsive unitcomprising an axial member of relatively small diameter and a radiallyouter annular shell of relatively large external diameter, said shellbeing fixed at its inner periphery to said axial member and formingtherewithin a reservoir of substantial size radially and longitudinallyof the motor mechanism, means for connecting the interior of said shellto a source of pressure different from the atmosphere, and a controlvalve mechanism carried by said axial member and having connection withsaid control chamber, said reservoir and the atmosphere and normallyconnecting said control chamber to the atmosphere, said valve mechanismbeing operative for disconnecting said control chamber from theatmosphere and connecting it to said reserfluid pressure responsivemeans exposed to pressure in said control chamber and to the atmosphereand connected to said valve mechanism to oppose motor energizingmovement thereof.

10. A fluid pressure motor comprising a casing of substantial diameter,a pressure responsive unit therein dividing said casing to form aconstant pressure chamber and a control chamber, said pressureresponsive unit comprising a radially relatively small axial member anda radially outer annular shell of relatively large external diameterhaving an external substantially cylindrical surface of slightly smallerdiameter than said casing and coaxial therewith, said shell being fixedat its inner periphery to said axial member and forming therewith areservoir of substantial size radially and longitudinally of the motormechanism, said pressure responsive unit further comprising a rollingdiaphragmhaving an inner portion lying over and fixed at one end to saidcylindrical shell portion and secured at its other end to said motorcasing, and a control valve mechanism carried by said axial member andhaving connection with said control chamber, said reservoir and theatmosphere and normally connecting said control chamber to theatmosphere, said reservoir having means for connecting it with a sourceof vacuum, said control valve mechanism being operative fordisconnecting said control chamber from the atmosphere and connecting itto said reservoir to eifect a rapid evacuation of said control chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,457,665 Lucas June 5, 1923 2,745,383 Hupp May 15, 1956 2,818,835 HuppJan. 7, 1958 2,842,101 Price July 8, 1958 2,871,827 Price Feb. 3, 19592,880,704 Price Apr. 7, 1959 FOREIGN PATENTS 350,696 Germany Mar. 23,1922

